Writing Systems of the World 3, Exercise 1: phono-semantic compounds

Per the Chinese characters article, phono-semantic compounds make up roughly
58% of about 3,500 frequently used characters in Standard Chinese.

3,500 x 0.58 = 2,030, so roughly 2,000 characters.

Why it undermines "picture writing": in these characters one part hints at
the sound, as in the rebus principle from Chapter 2. Pure pictographic or
meaning-only signs are a minority (the article gives about 18% pure signs and
about 5% pure semantographs). Chinese writing is a mix of meaning and sound.